Prior art toothbrushes are typically fixed and the ends of the bristles lie in a plane that is flat, concave or convex, or a combination of these. A toothbrush the bristles of which lie in a concave plane are best for brushing the outer surface of teeth, but are not best adapted for brushing the inner surface of teeth. A toothbrush the ends of the bristles of which lie in a convex plane are best for brushing the inner surface of teeth, but are not best adapted for brushing the outer surface of teeth. A toothbrush the ends of the bristles of which lie in a flat plane compromise between these two extremes but do not do the best job of brushing the inner surface or the outer surface of teeth.
Accordingly, a toothbrush is needed that is easily adjustable during use to configure the bristles to best brush both the inner surface and the outer surface of teeth.